1. Field of the Invention
The present invention relates to sensor devices used typically in vehicles and a range of electronic devices.
2. Background Art
As shown in FIG. 5, a conventional sensor device includes angular velocity sensor 1 for outputting an angular velocity sensing signal, and acceleration sensor 2 for outputting an acceleration sensing signal.
A prior art related to the present invention is disclosed, for example, in Japanese Patent Unexamined Publication No. 2005-283481.
The conventional sensor device has a disadvantage of its low detection accuracy.
Let's take an example of an automobile navigation system in a vehicle equipped with the above conventional sensor device. More specifically, let's assume that the above vehicle is traveling in a multistory parking lot. The sensor device uses gravitational acceleration information from acceleration sensor 2 for correcting angular velocity information from angular velocity sensor 1. This enables detection of a spiral travel of the vehicle in the multistory parking lot.
However, in the conventional sensor device, an output on gravitational acceleration from acceleration sensor 2 and an output from angular velocity sensor 1 are not linked on a time-point basis. Accordingly, if there is a difference in time point of signal transmission between a circuit of angular velocity sensor 1 and a circuit of acceleration sensor 2, the angular velocity information cannot be accurately corrected using the gravitational acceleration information from acceleration sensor 2. This results in low detection accuracy.